I have a dataset with 9 continuous observed variables assessed across 3 groups that differ in their sample size.

To add an additional level of complexity each of these variables is sampled within an individual at 4 points in time (1 s apart) so there is a degree of auto correlation. Is there an appropriate way to build this into the model?

I would like to run a multiple sample path analysis but am unable to find an appropriate example/code to get started in specifying the analysis.